Coaxial electrical connector

ABSTRACT

A coaxial electrical connector includes a dielectric housing having a front mating face and a rear face. A first, central terminal-receiving passage extends in a direction between the faces, along with at least one second, auxiliary terminal-receiving passage. At least one auxiliary terminal is received in the second passage. A center terminal is received in the first passage and includes an elongated mating portion projecting toward the mating face of the housing and defining a center axis. The elongated mating portion has a front mating end and a rear end. A terminating portion is spaced radially of the mating portion. A connecting portion joins the mating portion and the terminating portion. The connecting portion includes a stabilizing section which extends rearwardly along the axis from the rear end of the mating portion. The stabilizing section bears against a section of the first passage in the housing to stabilize the elongated mating portion of the center terminal.

FIELD OF THE INVENTION

This invention generally relates to the art of electrical connectorsand, particularly, to a coaxial type electrical connector which has acenter contact or terminal element.

BACKGROUND OF THE INVENTION

Coaxial electrical connectors are used in a wide variety of applicationsfor transmitting direct current, such as in charger sockets for suchdevices as cellular telephones or the like. Such coaxial connectorsinclude a center terminal and at least one auxiliary terminal spacedtransversely or radially of the center terminal. Distal ends of thecenter terminal and the auxiliary terminal respectively mate with thepositive and negative electrodes of a mating element such as a femalecoaxial connecting device. Opposite ends of the terminals may beconnected, as by soldering, to appropriate circuit traces on a printedcircuit board for transmitting current. In these connector arrangements,the center terminal is a critical component of the connector.

The terminals of such connectors typically are stamped and formed ofconductive sheet metal material. In order to reduce the contactresistance of the coaxial connector to improve the stability of thecircuit, the mating end of the center terminal is formed or rolled intoa cylindrical configuration, and the terminating end of the centerterminal is appropriately stamped and formed into a configuration formounting the terminal and terminating the terminal, such as to theprinted circuit board. Processing the cylindrical mating end of theterminal requires multi-axis rolling and forming technology which iscomplex and may result in inconsistent quality of the terminal and theconnector. In addition, it is difficult to fix the center terminal inthe housing of the connector without unduly increasing the size of thehousing or affecting the stability of current transmission.

In an attempt to solve these various problems, FIG. 1 shows a coaxialconnector, generally designated 10, as disclosed in Chinese Patent No.01280613. The connector includes an insulating housing, generallydesignated 12; a center terminal, generally designated 14; and a pair ofauxiliary terminals, generally designated 16 and 18. The center terminalis inserted into a passage 12 a of housing 12; auxiliary terminal 16 isinserted into a passage 12 b in the housing; and auxiliary terminal 18is inserted into a passage 12 c in the housing. Center terminal 14includes a hollow cylindrical mating portion 14 a, a solder tail portion14 b and a right-angled connecting portion 14 c joining the matingportion to the solder tail portion. A pair of mounting interferencewings 14 d project outwardly from opposite sides of the center terminalgenerally at the right-angled connecting portion 14 c thereof. Themounting interference wings have outwardly projecting teeth 14 e.

Still referring to FIG. 1, when center terminal 14 is inserted intopassage 12 a in housing 12, the mounting interference wings 14 d areinserted into a pair of slots 12 d at opposite sides of passage 12 awith an interference fit to hold the center terminal in the housing.However, since mounting wings 14 d are plate-like members and theircontact area with inner walls of the housing is rather small, theinterference affect is rather small and it is difficult to ensure stablemounting of the center terminal. Unstable mounting will affect thestability of current transmission. The mounting interference wingscannot be made significantly larger to increase the holding affect onthe center terminal without significantly increasing the size of housing12 which would be undesirable.

FIG. 2 shows another coaxial cable, generally designated 20, accordingto the prior art. This connector includes an insulating housing,generally designated 22; a center terminal, generally designated 24; anda pair of auxiliary terminals, generally designated 26 and 28. Thecenter terminal is inserted into a passage 22 a in the housing, and theauxiliary terminals 26 and 28 are inserted into a pair of passages 22 band 22 c, respectively, in the housing. Again, center terminal 24 has acylindrical mating portion 24 a, a solder tail portion 24 b and aconnecting portion 24 c joining the cylindrical mating portion to thesolder tail portion. The mating portion has a pair of resilient contactfingers 24 d to enhance the contact engagement with a mating femaleconnecting device. In order to improve the holding capabilities ofcenter terminal 24 within housing 22, a pair of mounting interferencehooks 24 e are inclined outwardly from opposite sides of mating portion24 a near connecting portion 24 c. Although hooks 24 e (FIG. 2) mightimprove the stability of the center terminal versus wings 14 d (FIG. 1),the improvement is rather small even when combined with any interferenceeffect generated by connecting portion 24 c with housing 22. In order toincrease the holding force, either the size of connecting portion 24 cor wing portions 24 e must be significantly increased which, in turn,will undesirably increase the transverse dimensions of housing 22. Thiswould be undesirable when miniaturization of coaxial cables isever-increasing.

The present invention is directed to solving these various problems ofincreasing the holding forces and, particularly, the stability of acenter terminal in coaxial electrical connectors.

SUMMARY OF THE INVENTION

An object, therefore, of the invention is to provide a new and improvedcoaxial electrical connector of the character described.

In the exemplary embodiment of the invention, the connector includes adielectric housing having a front mating face and a rear face. A first,central terminal-receiving passage extends in a direction between thefaces, along with at least one second, auxiliary terminal-receivingpassage. At least one auxiliary terminal is received in the secondpassage. A center terminal is received in the first passage and includesan elongated mating portion projecting toward the mating face of thehousing and defining a center axis. The elongated mating portion has afront mating end and a rear end. A terminating portion is spacedradially of the mating portion. A connecting portion joins the matingportion and the terminating portion. The connecting portion includes astabilizing section which extends rearwardly along the axis from therear end of the mating portion. The stabilizing section bears against asection of the first passage in the housing to stabilize the elongatedmating portion of the center terminal.

According to one aspect of the invention, the elongated mating portionof the center terminal is cylindrical. The stabilizing section of theconnecting portion is arc-shaped and generally coincident with thecylindrical mating portion. The center terminal may be stamped andformed of sheet metal material, and the arc-shaped stabilizing sectionthereby can be formed as a continuation of the cylindrical matingportion. As disclosed herein, the connecting portion of the centerterminal is generally J-shaped and includes a plate section extendingbetween the arc-shaped stabilizing section and the terminating portionof the center terminal.

Other features of the invention include the elongated mating portion ofthe center terminal including an angled barb near a rear end thereof forengaging an inside retaining surface of the first passage of the housingto retain the center terminal in the passage. The plate section of theJ-shaped connecting portion of the center terminal includes a projectionbearing against a wall of the first passage to further stabilize themating portion of the center terminal. Both the center terminal and theauxiliary terminal include terminating portions formed as solder tailsfor electrical connector to a printed circuit board.

Other objects, features and advantages of the invention will be apparentfrom the following detailed description taken in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of this invention which are believed to be novel are setforth with particularity in the appended claims. The invention, togetherwith its objects and the advantages thereof, may be best understood byreference to the following description taken in conjunction with theaccompanying drawings, in which like reference numerals identify likeelements in the figures and in which:

FIG. 1 is an exploded perspective view of a prior art coaxial connectoras described in the Background, above;

FIG. 2 is an exploded perspective view of another coaxial connectoraccording to the prior art and also described in the Background, above;

FIG. 3 is a perspective view looking at the front mating end of acoaxial connector according to the invention;

FIG. 4 is a perspective view looking at the rear end of the coaxialconnector of FIG. 3;

FIG. 5 is an exploded perspective view of the coaxial connector of FIG.3;

FIG. 6 is a vertical section taken generally along line 6—6 in FIG. 5;

FIG. 7 is a vertical section taken generally along line 7—7 in FIG. 3;and

FIG. 8 is a view similar to that of FIG. 7, with a mating connectingdevice inserted into the connector.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings in greater detail, and first to FIGS. 3 and 4,the invention is embodied in a coaxial electrical connector, generallydesignated 30, which includes a dielectric housing, generally designated32, mounting a center terminal, generally designated 34, and anauxiliary terminal, generally designated 36.

Referring to FIGS. 3, 5 and 6, dielectric housing 32 has a front matingface 38 and a rear face 40. The housing may be molded of plasticmaterial. A top face 42 and a side face 44 of the housing extend betweenthe front and rear faces. A receptacle 46 opens at the front face of thehousing for receiving a mating connecting device as described below inrelation to FIG. 8. Top face 42 has a pair of elongated openings 48 and50, and side face 44 has an elongated opening 52. A first, centralterminal-receiving passage 54 extends in a direction between the frontand rear faces of the housing and opens in the rear face as seen in FIG.5. A second, auxiliary terminal-receiving passage 56 also opens at therear face of the housing and extends thereinto generally parallel tofirst passage 54. As seen best in FIG. 5, a connecting slot 58 joinsfirst passage 54 with elongated opening 48. A pair of holding grooves 60are formed at opposite sides of elongated opening 48 and extend inwardlyfrom rear face 40 to abutment shoulders 62. Similarly, a pair of holdinggrooves 64 are formed at opposite sides of elongated opening 50 and runfrom rear face 40 to abutment shoulders 66. The first, centralterminal-receiving passage 54 has a side slot 68 (FIG. 5) which runsfrom rear face 40 to a retaining shoulder or surface 70 shown in FIG. 6.Finally, the second, auxiliary terminal-receiving passage 56 has a lowerportion 72.

Referring to FIG. 5, center terminal 34 may be stamped and formed ofconductive sheet metal material. The center terminal includes anelongated, cylindrical mating portion 74 defining a center axis 75. Themating portion has a semi-spherical front mating end 74 a and a rear end74 b. A terminating portion in the form of a solder tail 76 is spacedradially from and extends generally parallel to cylindrical matingportion 74. A J-shaped connecting portion 78 joins mating portion 74 toterminating portion 76. The connecting portion has an arc-shapedstabilizing section 78 a which extends rearwardly along axis 75 fromrear end 74 b of mating portion 74. The J-shaped connecting portion 78has a plate section 78 b which extends from the arc-shaped stabilizingsection 78 a to a horizontal or right-angled plate section 80 at therear of terminating portion 76. Plate section 80 forms a pair of holdingwings 80 a which project outwardly from terminating portion or soldertail 76 at the rear end thereof. An angled barb 82 projects outwardlyfrom cylindrical mating portion 74 near rear end 74 b thereof. Finally,a bearing projection 84 projects transversely outwardly from platesection 78 b of the J-shaped connecting portion 78 of center terminal34.

Still referring to FIG. 5, auxiliary terminal 36 also is stamped andformed of conductive sheet metal material in a generally U-shape toinclude a bottom plate 86, a side plate 88 and a top terminating portionin the form of a solder tail 90. A spring contact portion 92 is formedout of an opening 94 in bottom plate 86. The bottom plate also has teeth96 stamped out of the side edges thereof. Side plate 88 has a forwardlyextending, cantilevered spring contact arm 98 formed with an inwardlybowed contact surface 98 a. A support bar 100 is formed at the distalend of spring arm 98. Like bottom plate 86, side plate 88 is stampedwith teeth 102 in the side edges thereof.

Referring to FIGS. 4, 5 and 7, center terminal 34 is inserted into firstpassage 54 through rear face 40 of housing 32. The center terminal isinserted until cylindrical mating portion 74 extends forwardly towardthe front mating face of the housing and into receptacle 46 as seen inFIG. 7. When fully inserted, angled barb 82 (FIGS. 5 and 7) snaps intoengagement with retaining shoulder or surface 70 (FIG. 6) within passage54 of the housing. Terminating portion 76 moves into the elongatedopening 48 in top face 42 of the housing as seen in FIG. 4. Theterminating portion projects upwardly or outwardly of the opening, asshown, for connection, as by soldering, to an appropriate circuit traceon a printed circuit board (not shown). When the center terminal isfully inserted into passage 54 as shown in FIGS. 4 and 7, it can be seenthat the arc-shaped stabilizing section 78 a of the terminal bearsagainst a rear section of the passage. With the stabilizing section, inessence, being formed coincident with or as a continuation/extension ofthe cylindrical mating portion 74 of the terminal, this stabilizingsection considerably stabilizes the mating terminal without having toenlarge the housing in a direction generally transversely of the matingportion (i.e., axis 75, FIG. 5).

Still further, when center terminal 34 is fully inserted into passage54, holding wings 80 a (FIG. 5) abut against abutting shoulders 62 ofthe housing at opposite sides of elongated opening 48, as plate section80 ridges into holding grooves 60 at opposite sides of the elongatedopening. Bearing projection 84 bears against a wall or surface ofconnecting slot 58. All of these interengaging components between thecenter terminal and the housing also ensure stabilization of theterminal, including terminating portion 76, to stabilize the currentthrough the center terminal.

Auxiliary terminal 36 is inserted into passage 56 in housing 32 throughrear face 40 of the housing. When inserted, bottom plate 86 of theterminal enters lower portion 72 of the passage and terminating portion90 enters elongated opening 70 in the top face 42 of the housing wherebythe terminating portion or solder tail 90 projects upwardly out of theopening as shown in FIG. 4, for connection, as by soldering to anappropriate circuit trace on the printed circuit board. As seen in FIG.4, spring contact arm 98 is exposed within elongated opening 52 in sideface 44 of a housing. Support arm 100 abuts against internal ledges 104of the housing. When the auxiliary terminal is fully inserted intopassage 56, teeth 96 at opposite edges of bottom plate 86 bite into theplastic material of the housing within lower portion 72 of the passage,while teeth 102 at opposite edges of side plate 88 also bite into theplastic material of the housing within passage 56 to solidly retain theauxiliary terminal within the passage. When the auxiliary terminal isfully inserted into passage 56, cantilevered spring arm 98 (with contactsurface 98) projects into receptacle 46. Spring contact portion 92 alsoprojects into the receptacle as seen in FIG. 7.

FIG. 8 shows a mating connecting device 106 inserted into receptacle 46of housing 32 of coaxial connector 30. The mating connecting device hasa socket 108 for receiving cylindrical mating portion 74 of centerterminal 34. The mating connecting device has an outer cylindricalsurface 110 which engages spring contact portion 92 of auxiliaryterminal 36. Although not visible in FIG. 8, contact surface 98 a (FIG.5) of cantilevered spring contact arm 98 also engages outer surface 110of the mating connecting device. Although not visible in the drawing, apositive electrode will be provided within socket 108 for engagingmating portion 74 of center terminal 34, and negative electrode meansare provided on outer surface 110 of the mating connecting device forengaging spring contact portion 92 and contact surface 98 a of theauxiliary terminal.

It will be understood that the invention may be embodied in otherspecific forms without departing from the spirit or centralcharacteristics thereof. The present examples and embodiments,therefore, are to be considered in all respects as illustrative and notrestrictive, and the invention is not to be limited to the details givenherein.

1. A coaxial electrical connector (30), comprising: a dielectric housing(32) having a front mating face (38) and a rear face (40), a first,central terminal-receiving passage (54) extending in a direction betweensaid faces and at least one second, auxiliary terminal-receiving passage(56); at least one auxiliary terminal (36) received in said secondpassage; and a center terminal (34) received in the first passage, thecenter terminal including: an elongated mating portion (74) projectingtoward the mating face of the housing and defining a center axis (75),the elongated mating portion having a front mating end (74 a) and a rearend (74 b); a terminating portion (76) spaced radially of the matingportion; and a connecting portion (78) joining the elongated matingportion and the terminating portion, the connecting portion including astabilizing section (78 a) which extends rearwardly along said axis (75)from the rear end of the mating portion, the stabilizing section bearingagainst a section of the first passage (54) in the housing to stabilizethe elongated mating portion of the center terminal, charactised inthat: said elongated mating portion (74) of the center terminal (34) iscylindrical, the stabilizing section (78 a) of the connecting portion(78) of the center terminal is arc-shaped and generally coincident withthe cylindrical mating portion, and said connecting portion (78) of thecenter terminal (34) is generally J-shaped and includes a plate section(78 b) extending between the arc-shaped stabilizing section (78 a) andthe terminating portion (76) of the center terminal.
 2. The coaxialelectrical connector of claim 1 wherein said center terminal (34) isstamped and formed of sheet metal material, and the arc-shapedstabilizing section (78 a) is formed as a continuation of thecylindrical mating portion (74).
 3. The coaxial electrical connector ofclaim 1 wherein said elongated mating portion (74) of the centerterminal (34) includes an angled barb (82) near a rear end (74 b)thereof for engaging an inside retaining surface (58) of the firstpassage (54) in the housing (32) to retain the center terminal in thepassage.
 4. The coaxial electrical connector of claim 1 wherein theplate section includes a projection (84) bearing against a wall (58) ofthe first passage (54) in the housing to further stabilize the matingportion of the center terminal.
 5. The coaxial electrical connector ofclaim 1 wherein the terminating portion of the center terminal comprisesa tail portion (76) for electrical connection to a printed circuitboard.
 6. The coaxial electrical connector of claim 5 wherein saidauxiliary terminal (36) includes a tail portion (90) for electricalconnection to the printed circuit board.